A ban is a formal or informal prohibition of something. Bans are formed for the prohibition of activities within a certain political territory. Some see this as a negative act (equating it to a form of censorship or discrimination) and others see it as maintaining the "status quo". Some bans in commerce are referred to as embargoes. Ban is also used as a verb similar in meaning to "to prohibit".
During the apartheid régime in South Africa, the National Party government issued banning orders to individuals seen to be threats to its power — often black politicians or organizations — these banning orders acted as suppression orders. Individuals banned by the Suppression of Communism Act, 1950 (which effectively defined "Communism" as opposition to the government) could not communicate with more than one person at any time unless at home (thus preventing them from engaging in political activities), travel to outside a specific magisterial district without government approval, or leave the country.
Existing publications may be banned, and new publications prohibited from discussing certain topics or taking certain viewpoints. Censorship is the enacting and enforcing of such bans.